Polyamide moulding compound and use thereof

ABSTRACT

The present invention relates to polyamide moulding compounds which have very low distortion with good mechanical properties. This is achieved by a combination of transparent polyamide with fibrous reinforcing materials and also particulate fillers. The moulding compounds according to the invention are used for the production of any moulded articles, semi-finished products or finished products.

The present invention relates to polyamide moulding compounds which havevery low distortion with good mechanical properties. This is achieved bya combination of transparent polyamide with fibrous reinforcingmaterials and also particulate fillers. The moulding compounds accordingto the invention are used for the production of any moulded articles,semi-finished products or finished products.

Polyamides are widespread nowadays as structural elements for theinterior and exterior sphere, which can be attributed essentially to theoutstanding mechanical properties.

An improvement in the mechanical properties, such as strength andrigidity, can be achieved in particular by the addition of fibrousreinforcing materials, e.g. glass fibres. However frequently increaseddistortion of the moulded parts is associated with the addition offibrous reinforcing materials. The consequence of this is that onlysmall contents of fibrous reinforcing materials, or rather onlyisotropic fillers, such as glass balls, can be used if distortion isregarded as a critical parameter for the moulded part The mouldingcompounds obtained in this way then have only a low modulus ofelasticity in tension in the moulded part.

The addition of particulate fillers effects, on the one hand, areduction in the distortion but leads, on the other hand, to animpairment with respect to the mechanical properties, such as strengthand breaking elongation.

Starting herefrom, it was the object of the present invention to providepolyamide moulding compounds with which there can be produced mouldedarticles with good mechanical properties and at the same time lowdistortion and which do not have the previously described disadvantagesof the state of the art.

This object is achieved with respect to the polyamide moulding compoundby the features of claim 1, with respect to the moulded articles by thefeatures of claim 15 and with respect to use by the features of claim20. The further dependent claims reveal advantageous developments.

The polyamide moulding compound according to the invention comprises 40to 79% by weight at least of a transparent polyamide, 15 to 49% byweight at least of a fibrous reinforcing material and 6 to 30% by weightof a particulate filler. In addition, further additives can be containedas complement to 100% by weight. Preferred compositions comprise 40 to69% by weight, preferably 40 to 55% by weight, of the transparentpolyamide, 25 to 49% by weight, preferably 30 to 49% by weight, of thefibrous reinforcing material, 6 to 30% by weight of the particulatefiller and also if necessary, as complement to 100% by weight, at leastone further additive. However there should not be understood asadditives within the scope of the present invention polyamide oligomers.

A particular feature of the present invention is that good mechanicalproperties can be achieved by moulded articles produced herefrom by theclaimed combination on the one hand and the moulded articles accordingto the invention have at the same time a substantially lower distortionin comparison with known moulded articles.

With respect to the fibrous reinforcing materials, basically norestrictions exist. Preferably, these are selected from the groupcomprising glass fibres, carbon fibres, metal fibres, aramide fibres,whiskers and mixtures thereof. There should be understood by whiskersneedle-like monocrystals comprising metals, oxides, borides, carbides,nitrides, polytitanate, carbon etc. with a generally polygonalcross-section, e.g. potassium nitanate-, aluminium oxide-, siliconcarbide-whiskers. In general, whiskers have a diameter of 0.1 to 10 μmand a length in the mm to cm range. At the same time, they have hightensile strength. Whiskers can be produced by deposition from the gasphase in the solid (VS mechanism) or from a three-phase system (VLSmechanism).

The glass fibres preferably have a diameter of 5 to 20 μm andparticularly preferred of 5 to 10 μm. Preferably, glass fibres with around, oval or rectangular cross-section are used. The glass fibresthereby comprise preferably E-glass. The glass fibres can thereby beadded as endless fibres or as cut glass fibres, the fibres being able tobe equipped with a suitable sizing system and a bonding agent or bondingagent system, e.g. on a silane basis.

All the fillers known to the person skilled in the art are possible asparticulate fillers. There are included herein in particular particulatefillers selected from the group comprising talcum, mica, silicates,quartz, titanium dioxide, wollastonite, kaolin, silicic acids, magnesiumcarbonate, magnesium hydroxide, chalk, ground or precipitated calciumcarbonate, lime, feldspar, barium sulphate, permanently magnetic ormagnetisable metals or alloys, glass balls, hollow glass balls, hollowspherical silicate fillers and mixtures thereof.

Transparent polyamides in the sense of the present invention arepolyamides which have a defined light transmission.

In particular the polyamides, the light transmission of which is atleast 70%, are included herein if the polyamide is present in the formof a plate, e.g. a round plate, with a thickness of 2 mm. Round platesof 75×2 mm are produced on an Arburg injection moulding machine in thepolished mould, the cylinder temperature being between 240 and 340° C.and the mould temperature between 20 and 140° C. The measurement of thelight transmission is implemented according to ASTM D 1003-61 on themeasuring apparatus Haze Gard plus by the Byk Gardner company with CIElight type C at 23° C. The light transmission value is thereby indicatedin % of the irradiated light quantity.

Preferably transparent polyamides which have a light transmission of atleast 86%, particularly preferred of at least 90%, are used.

No restrictions exist with respect to the composition of the transparentpolyamides so that all the transparent polyamides or mixtures thereofwhich are known to the person skilled in the art can be used. There areincluded herein in particular the polyamides which are produced from atleast one diamine and at least one dicarboxylic acid and/or at least oneamino acid or a lactam. There are preferred hereby as diamine aliphaticand/or cycloaliphatic diamines with 6 to 17 C-atoms and/or diamines(C₆-C₁₇) with partially aromatic structures. There are used preferablyas dicarboxylic acids aliphatic and/or aromatic dicarboxylic acids with6 to 12 C-atoms. The amino acids are selected preferably from the groupof α, Ω amino acids with 6 to 12 C-atoms. The lactams are preferablyselected from the group of lactams with 6 to 12 C-atoms.

The transparent polyamides have a relative viscosity of 1.36-1.80,preferably 1.36-1.74, particularly preferred 1.41-1.69. The relativeviscosity is thereby determined according to DIN EN ISO 307, in 0.5%m-cresol solution at 20° C.

The transparent polyamides have a glass transition temperature (Tg) ofat least 120° C., preferably at least 130° C. The glass transitiontemperature is thereby determined by means of differential scanningcalorimetry (DSC) at a heating rate of 20° C./min according to the ISOstandard 11357-1/-2. The temperature at the turning point is indicated.

Transparent, amorphous polyamides are preferred. There are includedherein in particular the polyamides which, in the dynamic differentialscanning calorimetry (DSC) according to ISO 1357-1/-2, at a heating rateof 20° C./min, have a melting heat of at most 5 J/g, preferably at most3 J/g and particularly preferred at most 1 J/g.

The transparent amorphous polyamides are produced preferably from atleast one diamine and at least one dicarboxylic acid and/or at least oneamino acid or a lactam. Aliphatic and/or cycloaliphatic diamines with 6to 17 C-atoms and/or diamines (C₆-C₁₇) with partially aromaticstructures are preferred as diamine. There are used preferably asdicarboxylic acids aliphatic and/or aromatic dicarboxylic acids with 6to 12 C-atoms. The amino acids are selected preferably from the group α,ω amino acids with 6 to 12 C-atoms. The lactams are selected preferablyfrom the group of lactams with 6 to 12 C-atoms

The transparent amorphous polyamides have a relative viscosity of1.36-1.80, preferably 1.36-1,74, particularly preferred 1.41-1.69. Therelative viscosity is thereby determined according to DIN EN ISO 307, in0.5% m-cresol solution at 20° C.

The transparent amorphous polyamides have a glass transition temperature(Tg) of at least 120° C., preferably at least 130° C. The glasstransition temperature is thereby determined by means of differentialscanning calorimetry (DSC) at a heating rate of 20° C./min according tothe ISO standard 11357-1/-2. The temperature at the turning point isindicated.

Preferred transparent amorphous polyamides are selected from thefollowing group: PA 6I, PA 6I/6T, PA MXDI/6I, PA MXDI/MXDT/6I/6T, PAMXDI/12I, PA MXDI, PA MACM12, PA MACMI/12, PA MACMI/MACMT/12, PA6I/MACMI/12, PA 6I/6T/MACMI/MACMT, PA 6I/6T/MACMI/MACMT/12, PA MACM6/11,PA MACMI/MACM12 and mixtures thereof. The MACM can thereby be replacedby PACM up to 55% by mol, in particular up to 50% by mol.

In specially preferred embodiments there are used as base materialMACM-containing transparent amorphous polyamides or mixtures thereofwhich have respectively a relative viscosity of 1.41-1.69, preferably1.49-1.69. Their glass transition temperature is at least 130° C.,preferably at least 145° C.

In a further particular embodiment, a transparent amorphous polyamide isused as base material from the group MACM 12, MACMI/12 and mixturesthereof which have respectively a relative viscosity of 1.41-1.69,preferably 1.49-169. Their glass transition temperature is at least 130°C., preferably at least 145° C.

Of course the thermoplastic polyamide moulding compounds according tothe invention can contain in addition normal additives which are knownin general to the person skilled in the art and are selected from thegroup comprising impact strength modifiers, preferably so-called MBS orcore-outer layer impact strength modifiers, e.g. based onmethacrylate-butadiene-styrene, bonding agents, halogen-containingflameproofing agents, halogen-free flameproofing agents, stabilisers,age-protecting agents, antioxidants, antiozonants, light protectionagents, UV stabilisers, UV absorbers, UV blockers, inorganic heatstabilisers, organic heat stabilisers, conductivity additives, carbonblack, optical lighteners, processing aids, nucleation agents,crystallisation accelerators, crystallisation inhibitors, flow aids,lubricants, mould-release agents, softeners, pigments, colourants,marking materials and mixtures thereof.

The polyamide moulding compounds according to the invention can contain,for specific purposes, in addition also other polymers, such aspolyolefins, AN polymers, functionalised copolyolefins and ionomers.

Further embodiments provide that the polyamide moulding compoundcontains from 21 to 60% by weight, preferably from 31 to 60% by weight,specially preferred from 45 to 60% by weight, particularly preferredfrom 45 to 55% by weight, of the fibrous reinforcing materials and theparticulate fillers in total.

The reinforcing materials are always present in at least the samequantity (% by weight) as the fillers.

The invention comprises in addition moulded articles produced with theabove-described moulding compound. These moulded articles preferablyhave a distortion of ≦2.7 %, particularly preferred ≦2.3%. It should beemphasised thereby that, despite this low distortion, the mechanicalproperties of the moulded articles remain unaffected. Thus the mouldedarticle preferably has a modulus of elasticity in tension of ≧8000 MPa,in particular ≧10000 MPa. With respect to the tensile strength, values≧100 MPa, and in particular ≧140 MPa are preferred. The polyamidemoulding compound preferably has a breaking elongation of ≧1.5%,particularly preferred ≧2.0%.

Finally the invention also relates to the use of the above-describedmoulding compounds for the production of distortion-free mouldedarticles. The moulded articles are hereby selected preferably from thegroup comprising precisely fitting parts, mutually moveable parts,functional elements, operating elements, tracking elements, adjustmentelements, carrier elements, frame elements, switches and housings in thefield of electrics, electronics, energy and drive technology, mechanicalengineering, automobiles, furniture, sport, sanitary, hygiene, medicaltechnology, transport means, telecommunications, entertainmentelectronics, domestic appliances or electrical tools, produced byinjection moulding, extrusion or other shaping technologies, e.g.functional carriers in the cockpit area of an automobile, framecomponents of a sewing machine, mobile phone housings.

The production of the polyamide moulding compounds according to theinvention can be effected on normal compounding machines, such as e.g.single or twin-screw extruders or screw kneaders. As a rule, initiallythe polymer component is melted and the reinforcing material and/orfiller is fed into the melt at any points of the extruder, e.g. by meansof a side feeder. The compounding is effected preferably at set cylindertemperatures of 260° C. to 320° C. The polymer component and thereinforcing material and/or filler can however also all be metered intothe feed.

The present invention is intended to be explained in more detail withreference to the subsequent examples without wishing to restrict thelatter by the special embodiments shown here.

The moulding compounds were produced on a twin-screw extruder of thecompany Werner & Pfleiderer, type ZSK 25. Both the polyamide granulatesand the mineral were thereby metered into the feed via separate scales.The glass fibre was conveyed into the polymer melt via a side feeder 6housing units before the nozzle.

The temperature of the first housing was set at 100° C., that of theremaining housings at 280° C. A speed of rotation of 200 rpm and athroughput of 10 kg/h was used and degassed atmospherically. The strandswere cooled in the water bath, cut and the obtained granulate was driedat 120° C. for 24 h.

The thus produced moulding compounds were processed as follows into testbodies and tested.

Processing

The standard test bodies were produced on an injection moulding machineof the Arburg company, model Allrounder 320-210-750 Hydronica. In thecase of moulding compounds without PA 66, a material temperature of275-300° C. and a mould temperature of 80° C. was used. In the case ofmoulding compounds with PA 66, 300-308° C. and 100° C.

“Visitor card holders” were produced on an injection moulding machine ofthe Ferromatik company, model K85 D-S/2F, at set cylinder temperaturesof 270-290° C. and a mould temperature of 80-100° C.

Tests

Distortion:

The distortion was determined by means of an injection-moulded “Visitorcard holder” (see FIG. 1 in this respect). After storage of 14 days in anormal atmosphere (23° C., 50% relative humidity), the width is measuredand compared to the mould dimension (width of the cavity: 90.2 mm). Thegreater the difference, the greater is the distortion.

Modulus of elasticity in tension:

ISO 527 at a tension rate of 1 mm/min

ISO-test bar, standard: ISO/CD 3167, type A1, 170×20/10×4 mm,temperature 23° C.

Tensile Strength and Breaking Elongation:

ISO 527 at a tension rate of 50 mm/min

ISO-test bar, standard: ISO/CD 3167, type A1, 170×20/10×4 mm,temperature 23° C.

Impact Strength According to Charpy:

ISO 179/1eU

ISO-test bar, standard: ISO/CD 3167, type B1, 80×10×4 mm, temperature23° C.

Notch-Impact Strength According to Charpy:

ISO 179/1eA

ISO-test bar, standard: ISO/CD 3167, type B1, 80×10×4 mm, temperature23° C.

All the test bodies, apart from the “Visitor card holders”, were used inthe dry state. For this purpose, the test bodies were stored after theinjection moulding for at least 48 h at room temperature in drysurroundings.

EXAMPLES AND COMPARATIVE EXAMPLES

The following abbreviations are used in the following:

ABS Acrylnitrile-butadiene-styrene-copolymer

IPS Isophthalic acid (I)

LC-12 Laurinlactam

MACM Bis-(4-amino-3-methyl-cyclohexyl)methane

PC Polycarbonate

TPS Terephthalic acid (T)

RV Relative viscosity

The materials used in the examples are listed in Table 1. TABLE 1Relative Light viscosity at transmission 20° C. m-cresol, (2 mm plates)Material Trade name 0.5% Characterisation [%] Manufacturer MACM12 — 1.67*—/50/—/—/50 93.5 — MACMI/12 — 1.55 *—/32.4/32.4/—/34.6 92 —6I/6T/MACMI/MACMT — 1.45 *42.9/7.6/44.5/5.0/— 91 — 6I/6T — 1.41*50.2/—/33.2/16.6/— 91 — PC/ABS Bayblend T88- — — — Bayer AG, 4N**Germany PA 66 Ultramid S2701 2.70 in — — BASF AG, H2SO4, 1% Germany PA6GRILON A28 2.75 in — — EMS-CHEMIE H2S04, 1% AG, Switzerland Glass fibresVetrotex 995 — E-Glass — Saint-Gobain EC10-4.5 Diameter 10 mic Vetrotex,France Length 4.5 mm Calcium carbonate MILLICARB-OG — Calcium carbonate,— Omya AG, ground Switzerland Kaolin Quality China — Aluminium silicate— ECC Clay International, Great Britain**20% by weight glass fibres*HMD/MACM/IPS/TPS/LC-12 in mol %

Table 2 shows the composition of examples 1 to 5 according to theinvention and the herewith associated test results with respect to thedistortion and mechanical properties.

Table 3 shows the composition of examples 6 to 10 according to theinvention with associated distortion and mechanical properties.

Table 4 shows the composition of the comparative examples 11 to 16 withassociated test results.

Table 5 shows the composition of the comparative examples 17 to 19 withassociated test results. TABLE 2 Examples Number Materials Unit 1 2 3 45 MACM12 % by 40 55 40 40 50 weight MACMI/12 % by — — — — — weight6I/6T/MACMI/MACMT % by — — — — — weight 6I/6T % by — — — — — weightGlass fibres % by 30 30 30 40 40 weight Calcium carbonate % by 30 15 —20 10 weight Kaolin % by — — 30 — — weight Tests 1 2 3 4 5 Distortion %2.05 1.59 2.05 2.09 2.70 Modulus of elasticity in MPa 10230 8110 1063011760 10260 tension Tensile strength MPa 144 141 110 149 147 Breakingelongation % 2.5 3.2 1.6 2.3 2.6 Impact strength kJ/m² 34 56 16 37 45Notch-impact strength kJ/m² 8 11 4 9 11

TABLE 3 Examples Number Materials Unit 6 7 8 9 10 MACM12 % by — — — 4045 weight MACMI/12 % by — — 50 — — weight 6I/6T/MACMI/MACMT % by 50 — —— — weight 6I/6T % by — 50 — — — weight Glass fibres % by 40 40 40 49 49weight Calcium carbonate % by 10 10 10 11 6 weight Kaolin % by — — — — —weight Tests 6 7 8 9 10 Distortion % 1.69 1.27 2.28 2.19 2.51 Modulus ofelasticity in MPa 14020 14630 11420 13770 13040 tension Tensile strengthMPa 208 221 164 165 150 Breaking elongation % 2.2 2.4 2.4 2.2 2.1 Impactstrength kJ/m² 37 36 37 40 38 Notch-impact strength kJ/m² 8 9 9 11 13

TABLE 4 Comparative examples Number Materials Unit 11* 12 13 14 15 16PC/ABS % by 80 — — — — — weight MACM12 % by — 70 — — — — weight PA66 %by — — 60 40 51 43 weight PA6 % by — — — — 9 6 weight Glass % by 20 3030 30 30 30 fibres weight Calcium % by — — 10 — 10 — carbonate weightKaolin % by — — — 30 — 30 weight Tests 11 12 13 14 15 16 Distortion %2.75 3.33 6.09 5.14 6.56 3.99 Modulus of MPa 5900 6450 11380 13650 1085015010 elasticity in tension Tensile MPa 77 122 187 131 187 137 strengthBreaking % 2.0 3.9 3.2 1.5 3.7 1.4 elongation Impact kJ/m² — 61 82 24 9527 strength Notch- kJ/m² — 11 10 3 12 4 impact strength*Bayblend T88-4N

TABLE 5 Comparative examples Number Materials Unit 17 18 19 PC/ABS % byweight — — — MACM12 % by weight 60 — — PA66 % by weight — 50 45 PA6 % byweight — — — Glass fibres % by weight 40 40 49 Calcium % by weight — 106 carbonate Kaolin % by weight — — — Tests 17 18 19 Distortion % 3.275.32 5.11 Modulus of MPa 8730 14208 16520 elasticity in tension TensileMPa 146 217 241 strength Breaking % 3.4 3.0 2.7 elongation Impact kJ/m²64 92 105 strength Notch-impact kJ/m² 14 13 16 strength

The “Visitor card holders” produced from the moulding compounds of theexamples according to the invention show without exception a lowerdistortion than those made of the moulding compounds of the comparativeexamples.

The test bodies made of the moulding compound no. 11 with an amorphousPC/ABS blend as basis (Bayblend T88-4N, a commercial product by BayerAG) show in fact the lowest distortion in the comparative examples buteven this is still higher than that of the test bodies made of themoulding compounds according to the invention.

The test bodies made of the comparative moulding compounds (nos. 13-16and 18, 19) which are based on partially crystalline polyamides have asignificantly higher distortion still.

Even the test bodies made of solely reinforced comparative mouldingcompounds with an amorphous polyamide as basis (nos. 12 and 17) havehigher distortion than those of the moulding compounds according to theinvention with reinforcing materials and fillers.

The comparative examples show in addition that high moduli of elasticityin tension generally are accompanied by high distortion.

In this context, the moulding compound no. 11 in fact provides the testbodies with the lowest distortion within the comparative examples butthese also have the lowest modulus of elasticity in tension.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The preceding preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the disclosure in any way whatsoever.

In the foregoing and in the examples, all temperatures are set forthuncorrected in degrees Celsius and, all parts and percentages are byweight, unless otherwise indicated.

The entire disclosures of all applications, patents and publications,cited herein and of corresponding European application No. 06 014 372.4,filed Jul. 11, 2006, are incorporated by reference herein.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1. Polyamide moulding compound comprising 40 to 79% by weight at leastof a transparent polyamide, 15 to 49% by weight at least of a fibrousreinforcing material and 6 to 30% by weight of a particulate filler andalso if necessary, as complement to 100% by weight, at least one furtheradditive, polyamide oligomers being excluded as additive.
 2. Polyamidemoulding compound according to claim 1, characterised in that itcomprises 40 to 69% by weight, preferably 40 to 55% by weight, of thetransparent polyamide, 25 to 49% by weight, preferably 30 to 49% byweight, of the fibrous reinforcing material and 6 to 30% by weight ofthe particulate filler and also if necessary, as complement to 100% byweight, at least one further additive.
 3. Polyamide moulding compoundaccording to claim 1, characterised in that the at least one fibrousreinforcing material is selected from the group comprising glass fibres,carbon fibres, metal fibres, aramide fibres, whiskers and mixturesthereof.
 4. Polyamide moulding compound according to claim 3,characterised in that the glass fibres have a diameter of 5 to 20 μm, inparticular 5 to 10 μm.
 5. Polyamide moulding compound according to claim3, characterised in that the glass fibres have a round, oval orrectangular cross-section.
 6. Polyamide moulding compound according toclaim 3, characterised in that glass fibres made of E-glass arecontained.
 7. Polyamide moulding compound according to claim 1,characterised in that the at least one particulate filler is selectedfrom the group comprising talcum, mica, silicates, quartz, titaniumdioxide, wollastonite, kaolin, silicic acids, magnesium carbonate,magnesium hydroxide, chalk, ground or precipitated calcium carbonate,lime, feldspar, barium sulphate, permanently magnetic or magnetisablemetals or alloys, glass balls, hollow glass balls, hollow sphericalsilicate fillers and mixtures thereof.
 8. Polyamide moulding compoundaccording to claim 1, characterised in that the at least one transparentpolyamide is selected from the group of polyamides, the lighttransmission of which, measured according to ASTM D 1003-61 on a platecomprising the polyamide with a thickness of 2 mm, is at least 70%,preferably at least 86%, particularly preferred at least 90%. 9.Polyamide moulding compound according to claim 1, characterised in thatthe at least one transparent amorphous polyamide is selected from thegroup of polyamides which, in the differential scanning calorimetry, DSCaccording to ISO 1357-1/-2 at a heating rate of 20° C./min, have amelting heat of at most 5 J/g, preferably at most 3 J/g and particularlypreferred at most 1 J/g.
 10. Polyamide moulding compound according toclaim 1, characterised in that the transparent polyamide is an amorphouspolyamide which was obtained from respectively at least onepolyamide-forming diamine and/or dicarboxylic acid and/or amino acid orlactam.
 11. Polyamide moulding compound according to claim 9,characterised in that there are selected as diamine aliphatic and/orcycloaliphatic diamines with 6 to 17 C-atoms and/or diamines withpartially aromatic structures with 6 to 17 C-atoms, as dicarboxylic acidaliphatic and/or aromatic dicarboxylic acids with 6 to 12 C-atoms and asamino acid α, ω amino acids with 6 to 12 C-atoms.
 12. Polyamide mouldingcompound according to claim 1, characterised in that the polyamides areselected from the group of homo- and/or copolyamides based on PA 6I, PA6I/6T, PA MXDI/6I, PA MXDI/MXDT/6I/6T, PA MXDI/12I, PA MXDI, PA MACM12,PA MACMI/12, PA MACMI/MACMT/12, PA 6I/MACMI/12, PA 6I/6T/MACMI/MACMT, PA6I/6T/MACMI/MACMT/12, PA MACM6/11, PA MACMI/MACM12, MACM being able tobe replaced by PACM up to 55% by mol, in particular up to 50% by mol.13. Polyamide moulding compound according to claim 1, characterised inthat the additives are selected from the group comprising impactstrength modifiers, bonding agents, halogen-containing flameproofingagents, halogen-free flameproofing agents, stabilisers, age-protectingagents, antioxidants, antiozonants, light protection agents, UVstabilisers, UV absorbers, UV blockers, inorganic heat stabilisers,organic heat stabilisers, conductivity additives, carbon black, opticallighteners, processing aids, nucleation agents, crystallisationaccelerators, crystallisation inhibitors, flow aids, lubricants,mould-release agents, softeners, pigments, colourants, marking materialsand mixtures thereof.
 14. Polyamide moulding compound according to claim1, characterised in that the polyamide moulding compound contains from21 to 60% by weight of the fibrous reinforcing materials and theparticulate fillers in total.
 15. Moulded article, produced from apolyamide moulding compound according to claim
 1. 16. Moulded articleaccording to claim 14, characterised in that the moulded article has adistortion of less than or equal to 2.7%, in particular less than orequal to 2.3%.
 17. Moulded article according to claim 14, characterisedin that the moulded article has a modulus of elasticity in tension ofgreater than or equal to 8000 MPa, in particular greater than or equalto 10000 MPa.
 18. Moulded article according to claim 14, characterisedin that the moulded article has a tensile strength of greater than orequal to 100 MPa, in particular 140 MPa.
 19. Moulded article accordingto claim 14, characterised in that the polyamide moulding compound has abreaking elongation of greater than or equal to 1.5%, in particular2.0%.
 20. Use of the polyamide moulding compound according to claim 1for the production of distortion-free moulded articles.
 21. Useaccording to the claim 1, characterised in that the moulded articles areselected from the group comprising fibres, films, pipes, hollow bodiesor other semi-finished products or finished products from injectionmoulding, extrusion, pultrusion, injection blowing or other shapingtechnologies.